1. Field of the Invention
The present invention relates to electrode sensors, and particularly to an ionophore and a polymer membrane selective for aluminum (III) ion.
2. Description of the Related Art
Potentiometric sensors typically use an ion selective electrode (ISE). The voltage between a reference electrode and the ISE exposed to an analyte solution can be measured, and since this voltage is related to the activity of the analyte by the Nernst equation, the unknown concentration of the analyte can be computed. There are several different types and configurations of ion selective electrodes, with and without internal reference solutions. The ISE usually uses a semipermeable membrane or selectively permeable membrane that is selective for the cation or anion of interest. One type of membrane used in an ion selective electrode is a polymer membrane. The polymer membrane includes a polymer matrix, often of poly (vinyl chloride) (PVC), that is doped with an ionophore (an organic ion exchange agent). The membrane also may include a plasticizer to keep the polymer soft and amorphous so that the ion of interest can be transported between the aqueous analyte solution and the ionophore embedded in the polymer matrix. The plasticizer may also affect the dielectric constant of the polymer membrane. Plasticized polymers used for ISE membranes are sometimes described as viscous liquids and referred to in the literature as liquid membranes.
Wastewater often contains aluminum ions (Al3+). However, conventional aluminum sensors for detecting and measuring such contamination suffer from a wide variety of limitations, such as cost and difficulty in use. Thus, an ionophore and polymer membrane selective for aluminum (III) ion solving the aforementioned problems is desired.